METHOD FOR CREATING A CUSTOMIZED ARTHROPLASTY RESECTION GUIDE UTILIZING TWO-DIMENSIONAL IMAGING
Aspects of the present disclosure involve systems, methods, computer program products for customized arthroplasty cutting guides or jigs. In particular, the present disclosure provides for a method of creating a customized arthroplasty cutting jig from one or more two-dimensional (2D) images of the patient's joint. The method includes receiving the 2D images of the joint from an imaging device, reformatting the images, and creating a customized jig template from the images. One or more landmarks are electronically marked on one or more of the series of 2D images of the patient's joint through a computing device. Once the template for the cutting jig is created utilizing one or more of the electronic markers on the 2D images, a cutting or milling program is generated by the computing device that may then be provided to a milling machine to create the cutting jig corresponding to the milling program.
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This application claims priority under 35 U.S.C. §119 from U.S. provisional application No. 62/034,085 entitled “METHOD FOR CREATING A CUSTOMIZED ARTHROPLASTY RESECTION GUIDE UTILIZING TWO-DIMENSIONAL IMAGING,” filed on Aug. 6, 2014, the entire contents of which are fully incorporated by reference herein for all purposes.
TECHNICAL FIELDAspects of the present disclosure generally relate to systems and methods for creating and manufacturing customized arthroplasty cutting or resection guides for joint replacement procedures. More specifically, the present disclosure relates to methods for creating arthroplasty cutting guides customized to a particular patient from one or more two-dimensional images of a patient's joint taken from an imaging device.
BACKGROUNDThrough over-use, traumatic events and/or debilitating disease, a person's joint may become damaged to the point that the joint is repaired. One type of procedure to address damage to a person's joint is an arthroplasty procedure. Arthroplasty is a medical procedure where a joint of a patient is replaced, remodeled, or realigned, often done to relieve pain in the joint after damage. Damage to the joint may result in a reduction or wearing away of cartilage in the joint area, which operates to provide frictional, compressive, shear, and tensile cushioning within the joint. As such, reduction in cartilage in a joint causes pain and decreased mobility of the joint. To combat this joint pain, a patient may undergo the arthroplasty procedure to restore function and use back to the damaged joint.
One type of arthroplasty procedure is known as Total Knee Arthroplasty (TKA). In general, TKA involves replacing the diseased or damaged portion of the knee with metal or plastic components that are shaped to approximate the shape of the replaced portion or shaped to allow movement of the joint and relieve the joint pain. Thus, a TKA procedure may include replacement of a portion of the femur and a portion of the tibia that make up the knee joint. Similar procedures may be performed on other damaged joints, such as a hip, a shoulder, an elbow, and the like. General discussion of arthroplasty procedures herein are directed specifically to TKA-type procedures, but may be applied to arthroplasty procedures of other types of joints.
In a TKA procedure, a damaged portion of the distal region of the femur is removed and replaced with a metal or plastic component that is shaped to mirror or approximate the replaced portion. The metal or plastic component may be impacted onto the femur or fixed using a type of surgical cement or other fastening system. Further, a proximal portion of the tibia may also be removed and replaced with a generally flat metal or plastic component that is shaped to mirror or approximate the replaced portion. The tibia replacement implant may also be attached to the tibia through impaction onto the bone or fixed using a type of cement. In general, the femur implant and the tibia implant are mated to form a joint that approximates the shape and operation of the knee joint. In some examples, a plastic surface is placed between the femur implant and the tibia implant to prevent metal-on-metal interaction between the implants during use of the replaced joint.
As mentioned above, a TKA procedure often involves the removal and replacement of portions of the femur and/or tibia of the injured knee. During the removal, the portions of the femur and tibia may be cut, drilled, resurfaced, and the like to create a surface on the bones that mates with the respective implants. In one particular example, the ends of the bones (distal end of the femur and proximate end of the tibia) may be completely removed to create a generally flat surface to which the implants are mated. Once the mating surfaces for the implants are created on the receiving bones, the implants may then be attached to the bones as described above.
Although the broad outline of the TKA procedures is described above, there is much to consider when performing the procedure. For example, patients may undergo a preoperative planning phase of the procedure through one or more consultations with a doctor that could last a month or more before the TKA is performed. In addition, alignment of the implants in the joint with the rest of the patient's anatomy is crucial to the longevity of the implant and the implant's effectiveness in counteracting the pre-TKA joint condition. As such, systems and methods have been developed to produce customized arthroplasty cutting jigs that allow a surgeon to quickly and accurately perform the necessary resections of the bones that result in a successful TKA procedure. In particular, cutting jigs may be generally customized for the particular patient's joint undergoing the TKA procedure to ensure that the implants align with the patient's anatomy post-procedure. Through the use of such customized cutting jigs, the TKA procedure is both more accurate (ensuring more longevity to the implants) and quicker (reducing the time required for the surgical procedure, thereby reducing the potential for post-surgery complications).
In general, cutting guides or cutting jigs used in TKA procedures may attach to one or more bones of the knee and provide a cut line to the surgeon for use during the TKA surgery. In particular, a femur cutting jig may attach to the distal end of the femur and include a cut guide or line. A surgeon, during the procedure, inserts a saw device into or through the cut line to resect the distal end of the femur. Similarly, a tibia cutting jig may attach to the proximal end of the tibia and include a cut line that the surgeon uses to resect the proximal end of the tibia. In this manner, the ends of the femur and tibia are resected by the surgeon during the TKA procedure, thereby creating a smooth mating surface for the implants.
The cutting jigs used in the TKA procedure may attach to the bones of the knee in various ways. General cutting jigs (cutting jigs that do not incorporate customization to the particular patient's anatomy) may attach to the femur and tibia to provide the resection line for the surgeon. Such general cutting jigs often require the surgeon to align the cut line into the proper position during attachment of the cutting jig. As can be appreciated, such general cutting jigs result in vastly different quality of effectiveness, mostly based on the experience and skill of the surgeon. Customized cutting jigs, on the other hand, are designed to mate with the particular patient's femur and/or tibia to reduce the amount of incorrect attachment of the cutting jig to the patient's knee. Through the use of customized cutting jigs, surgeon error in TKA procedures may be greatly reduced.
The customization of the arthroplasty cutting jigs may vary from procedure to procedure. In one simple example, the customization may include merely selecting one jig from a group of generalized cutting jigs of various sizes in an attempt to match the size of the patient's anatomy. On the other end of the spectrum, the customized arthroplasty cutting jig may provide a mating surface that is the exact negative of the femur or tibia for attachment to the bone surface. Regardless of the customization of the cutting jig used, the jig should be designed to provide the proper location and orientation on the bones of the affected joint such that treatment of the region can be performed accurately, safely, and quickly.
Images of orthopedic joints that are candidates for partial or total replacement are often formed as MRI images, referred to here as “slices,” with each such image being a projection on a two dimensional image forming substrate. Each such MRI image is actually a three dimensional “voxel,” representing a thickness of approximately 2 mm of partial images of cortical bone, cancellous bone cartilage and open space, with each such material having its own range of grey scales in the MRI image. For a full three dimensional representation of an anatomical surface AS of interest, it is often necessary to provide tens to hundreds of MRI slices in two or more of three views (coronal or front view, axial or top view, and sagittal or side view) for a given anatomical component.
Many of the knee replacement procedures presently use what is characterized as “full segmentation” in order to represent a relevant portion of a femur or a tibia surface in three dimensions. This approach requires use of a dense, three dimensional grid of points to accurately represent a surface, especially a surface having cusps or sharp corners with very small associated radii of curvature. This approach has several disadvantages, including the following: (1) this approach is time consuming, often requiring 4-20 hours of intense numerical work to generate and check the accuracy of the grid point coordinates for a single surface; (2) because of the time required to implement this approach for a single surface, use of this approach in mass manufacturing of custom or semi-custom instruments is limited; (3) this approach may introduce geometrical errors, including closing errors; (4) because of the close spacing of grid points, polynomials of high mathematical degree are be used, which can introduce undesirable “ripples” in the mathematical surface produced by a full segmentation process; and (5) formation and analysis of a large number of MRI slices is required
It is with these and other issues in mind that various aspects of the present disclosure were developed.
SUMMARYOne implementation of the present disclosure may take the form of a method for creating a cutting jig for an arthroplasty procedure. The method includes the operations of receiving a plurality of two-dimensional images of a patient's joint the subject of the arthroplasty procedure, reformatting the two-dimensional images to approximate a true anatomical coordinate of the patient's joint, and locating a plurality of mating shapes within the reformatted plurality of two-dimensional images of the patient's joint, the plurality of mating shapes corresponding to a plurality of mating shapes of a cutting jig for use during the arthroplasty procedure. The method may also include the operations of generating a milling program based at least on the placement of the mating shapes within the reformatted plurality of two-dimensional images of the patient's joint and milling the cutting jig based at least on the milling program.
Another implementation of the present disclosure may take the form of a system for creating a cutting jig for an arthroplasty procedure from a plurality of two-dimensional images. The system includes a network connection for receiving a plurality of two-dimensional images of a patient's joint the subject of the arthroplasty procedure, the plurality of two-dimensional images generated utilizing a magnetic-resonance imaging machine and a computing device. The computing device comprise at least one processing device and a non-transitory memory device in communication with the at least one processing device for storing one or more instructions that, when executed by the at least one processing device, cause the computing device to perform certain operations. Such operations may include reformatting at least a portion of the two-dimensional images to approximate a true anatomical coordinate of the patient's joint, locating a plurality of mating shapes within the reformatted plurality of two-dimensional images of the patient's joint, the plurality of mating shapes corresponding to a plurality of mating shapes of a cutting jig for use during the arthroplasty procedure, generating a milling program based at least on the placement of the mating shapes within the reformatted plurality of two-dimensional images of the patient's joint, and transmitting the generated milling program over the network connection to a milling device for milling the cutting jig based at least on the generated milling program.
Aspects of the present disclosure involve systems, methods, computer program products, manufacture process and the like, for customized arthroplasty cutting guides or jigs. In particular, the present disclosure provides for a method of creating a customized arthroplasty cutting jig from one or more two-dimensional (2D) images of the patient's joint to undergo the arthroplasty procedure. The method includes receiving the 2D images of the joint from an imaging device, reformatting the images, and creating a customized jig template from the images. In general, one or more landmarks are electronically marked on one or more of the series of 2D images of the patient's joint through a computing device. These electronic markers on the series of 2D images correspond to landmarks of the patient's joint undergoing the arthroplasty procedure. Once the template for the cutting jig is created by the computing device utilizing one or more of the electronic markers on the 2D images, a cutting or milling program is generated by the computing device. The cutting or milling program may then be provided to a milling machine to create the cutting jig corresponding to the milling program. The cutting jig is thus customized to the landmarks identified in the series of 2D images of the patient's joint. Further, the procedure does not require the generation of a three-dimensional (3D) model of the patient's anatomy to create the customized nature of the cutting jig. Rather, by utilizing one or more mating shapes that contact the joint anatomy at particular contact points of the joint anatomy corresponding to the identified landmarks in the 2D images, the customization of the cutting jig is achieved. Further, because the procedure does not require the generation of a 3D model, the customized cutting jigs may be produced more quickly and efficiently than previous customization methods.
To aid in the description below of the customized arthroplasty cutting jigs and methods for creating said jigs, a brief discussion of the bone anatomy of the human knee is now included. As mentioned above, the present disclosure may be applied to any type of joint of a patient. However, for ease of understanding, the discussion herein is limited to particulars of the human knee as an example of the joint relating to the present disclosure procedure and apparatus.
Further, would be desirable to eliminate the full segmentation process and the associated three dimensional anatomical modeling of a femur surface, and to replace this approach with data obtained from relatively few MRI “slices,” as few as, for example, six two-dimensional slices, that permits flexibility in choice of contact points between the femur surface and the instrument (jig) that facilitates resectioning and removal of a portion of the knee component. It would be even more desirable to replace the full segmentation procedure, with its thousands of grid points, with a simpler, quicker procedure that works with as few as about twelve contact points between an anatomical surface, such as the posterior femur, and a resectioning mechanism, such as a jig that properly positions a cutting guide. In regards to the tibia, would be desirable to eliminate the full segmentation process and the associated three dimensional anatomical modeling of a tibia surface, among other things; and to replace this approach with data obtained from relatively few MRI “slices,” as few as five, for example, two-dimensional slices, that permits flexibility in choice of contact points between the tibia surface and the instrument (jig) that facilitates resectioning and removal of a portion of the knee component. It would also be desirable to replace the full segmentation procedure, with its thousands of grid points, with a simpler, quicker procedure that works with as few as about seven contact points between the anatomical surface and resectioning mechanism for the tibia component. Aspects of the present disclosure may involve a “sparse contact” approach that provides a cutting jig mechanism, which defines a cut plane for a tibia component of a knee.
Aspects of the present disclosure involve a “sparse contact” approach that provides a cutting jig mechanism, which provides a cut plane for a femur 6 component of a knee 8. A lower (distal) portion of the femur component, illustrated in
A femur cutting jig mechanism (FCJM or “jig”) 20, illustrated in isometric views in
Referring to
The “sparse contact” approach described herein relies on a small number (e.g., six or fewer) of spaced apart two-dimensional MRI images or “slices” of the femur anatomical surface, with each slice containing or illuminating one, two, or possibly more contact points between the femur anatomical surface and the jig 20 that helps define a cut plane position for resectioning and removing a portion of the femur. Using this approach, more than one jig contact point may be defined for a slice so that some jig contact points may be co-planar relative to the MRI slice and or relative to each other. The approaches discussed herein may have several advantages, including but not limited to: (1) the number of MRI slices actually formed and used is quite small (e.g., about 6) and represents about 5-10 percent of the total volume of the portion of the anatomy component of interest; (2) the number of contact points and associated coordinates needed for position stability of the jig is also small (e.g., about 12 or less, as compared with hundreds to thousands for a full segmentation approach); (3) the “design time” required to determine relevant component dimensions and coordinates of the contact points on the anatomical surface is estimated to be no more than 20 minutes and should decrease further as one accumulates experience in the dimensioning process; (4) it is anticipated that this “sparse contact” approach will permit semi-custom design and fabrication of the replacement components and associated tools; and/or (5) provides some flexibility for the orthopedic surgeon to exercise creativity and compensation in choices and modifications of some of the dimensions and angular orientations.
A femoral cutting jig 20 conforming with various aspects of the present disclosure includes a substrate 46 from which various jig contact points (JCPm) project, are otherwise supported or defined. In one possible implementation, the jig is a unified structure formed from a block of base material using a computer numerical control (CNC) machine. However, it is possible for the jig to be an assembly of various components that form the final cutting jig structure. Alternatively, the jig may be created through molding, machining, milling, forming, 3D printing, assembling, or other processes. The term “substrate” as used herein is meant to refer to a base structure upon which the various jig contact points and jig contact point supporting structures are provided or otherwise supported, and by which the relative positioning of the various jig contact points are maintained. As mentioned, the jig may be a unified structure and hence the substrate and jig contact points are formed from the same material and thus the relative positioning of the jig contact points is naturally maintained. Other processes, such as milling a base material or forming a jig in a mold, would provide a similar unified structure. It is not necessary, however, that the jig be unified structure in which case the substrate may be a frame or other structure or assembly on which various jig contact point defining structures are attached or otherwise associated.
The jig contact points are arranged and spaced such that a surgeon may press the jig onto the distal surface of the femur at the knee and the jig will be properly positioned when the jig contact points are seated on respective femoral contact points (CPm). Notably, there are a discrete number of jig contact points (e.g., 9-14) as opposed to full surfaces or far more numerous numbers of contact locations. The jig also includes a cutting guide support structure onto which may be mounted the cutting guide 40. When the jig is seated on the femur, the jig may be pinned to the femur to properly position the cutting guide so that a resection of the femur may be performed pursuant to a total knee replacement.
In regards to the tibia, a proximal, upper portion, of a tibia component 10, illustrated in
A tibia cutting jig mechanism (TCJM) or simply “jig” 20, illustrated in isometric views in
The jig 20 is positioned in contact with the top surface of the tibia 10 and oriented to properly position the cut plane guide 31. The jig, once positioned correctly, is pinned to the tibia by inserting three pins (not shown) through three corresponding bosses (33-1, 33-2, 33-3) projecting from the jig and defining apertures through which the pins are inserted. It may be necessary to predrill the femur, possibly using the bosses or drill guides, prior to placement of the pins. The cut plane guide 33 is mounted between two projections 30-1 and 30-2. The guide 31 is pinned to the tibia through two cut bar positioning apertures, CBA1 and CBA2, shown in
The “sparse contact” approach discussed here relies on a small number (e.g., five or fewer) of two dimensional MRI images or “slices” of the tibia, with each slice containing or illuminating one or two contact points between the anatomical surface (tibia) and the tibia cutting jig mechanism that helps define a cut plane position for resectioning and removing a portion of part of the tibial area of interest. This approach has one or more advantages: (1) the number of MRI slices used to identify femoral contact points for corresponding jig contact points is quite small (e.g., at most about five) and represents no more than about 5-10 percent of the total volume of the portion of the anatomy component of interest; (2) the number of contact points and associated coordinates needed for position stability of the jig is also small (e.g., at most about seven, as compared with hundreds to thousands for a full segmentation approach); (3) the “design time” required to determine relevant component dimensions and coordinates of the contact points on the anatomical surfaces of the tibia is estimated to be about 20 minutes and is expected to decrease further as one accumulates experience in the dimensioning process; (4) this “sparse contact” approach will permit semi-custom design and fabrication of the knee replacement components and associated tools; and (5) this approach provides some flexibility for the orthopedic surgeon to exercise creativity and compensation in choices and modifications of some of the dimensions.
Turning now to the posterior view of the lower femur illustrated in
In general, during a TKA procedure, portions of the distal end of the femur (such as that shown in
Beginning in operation 402, a series of two-dimensional (2D) images of the patient's joint on which the arthroplasty procedure is to be performed may be obtained or received through a network connection. The 2D images of the patient's joint may be obtained from an imaging device (such as an X-ray or magnetic resonance imaging (MRI) machine) from several aspects of the joint. For example,
While the embodiments herein are discussed in the context of the imaging being via an MRI machine, in other embodiments the imaging is via computed tomography (CT), X-ray, or other medical imaging methods and systems. Further, although it is discussed herein as a scan of the knee, the 2D images may be obtained for any joint or other area of the patient's body, such as images of the patient's ankle, hip, shoulder, etc. For example and as explained in more detail below, imaging of the patient's hip and ankle may also be utilized in the development of customized cutting jigs for TKA procedures.
Once the 2D images of the joint at issue are obtained, the images may be entered into a computing device for processing and to further the procedure through which the arthroplasty cutting jig is created in operation 404. The computing device may receive the images through any form of electronic communication with the imaging device. In one particular example, the 2D images may be obtained by the imaging device (such as the MRI imaging machine) and transmitted to a website accessible by the computing device. In general, however, the 2D images may be obtained from the imaging machine in any fashion for further processing by the computing device. Once received, the 2D images may be stored in a computer-readable medium for further processing by the computing device.
In operation 406, the 2D images of the joint are processed to reformat the images to convert the images from a machine-defined coordinate system to approximate a true anatomical coordinate system for the images and/or to identify one or more points or landmarks associated with the patient's joint that mate with contact points or surfaces of the customized cutting jig. In general, a true anatomical coordinate of the patient's joint corresponds to the natural alignment of the patient prior to damage to the joint. For example, true anatomical alignment of the patient's knee may correspond to an axial plane through the center of the knee parallel to the ground while the patient is walking. It should be appreciated, however, that reformatting the 2D images to achieve an image that is a true anatomical alignment of the knee is not required. Rather, the reformatting of the images may approximate images of true anatomical alignment of the knee. The images that illustrate the joint at a true anatomical coordinate system may be used for jig creation and to aid a surgeon in approving the jig placement in the damaged joint.
In one embodiment, an operator of the computing device may sit at a monitor or other interface of the computing device through which the images are viewed. Utilizing a software program executed by the computing device, the operator may view the 2D images and provide one or more electronic markers on at least one of the 2D images. These electronic markers may correspond to one or more reference points within the images for processing and reformatting of the images by the computing device and/or identify features or landmarks within the 2D images of the patient's anatomy that correspond to contact surfaces of the customized cutting jig. The operations to create the reference points and features of the customized cutting jig are described in more detail below.
In another embodiment, a program executed by the computing device may obtain the 2D images, determine the one or more reference points within the images, reformat the images to correspond to a true anatomical coordinate system, and/or identify the landmarks within the 2D images that correspond to contact surfaces of the customized cutting jig, with or without the aid of an operator of the computing device. In yet another embodiment, one or more of these operations are performed by the operator, while other operations are performed by the computer program. As such, any of the operations and methods described herein may be performed by an operator of the computing device or the computing device itself through hardware, software, or a combination of both hardware and software. The particular operations and considerations of operation 406 are discussed in more detail below with reference to
With the various electronic markers identified on the 2D image(s), the computing device may generate a program or computational information based on the electronic markers in operation 408. This computational information may be provided to a milling device, such as a computer numerical control (CNC) milling device in operation 410, to create the customized cutting jig for the arthroplasty procedure based at least on the computational information provided to the milling device. In general, a CNC machine or device is operated by programmed commands included in a program or list of commands to mill or create an apparatus based on the instructions provided in the commands. Thus, in this example, CNC milling machines translate the commands into control signals of a cutting device to mill a jig out of a jig blank according to the provided information. As pertaining to the method of
In one embodiment, the operations described below may be performed multiple times for the different bones that make up a particular joint. For example, in a TKA procedure, the operations of
Further, many of the operations may be performed multiple times. For example, the images may be reformatted as described below any number of times to approach images illustrating the joint in a true anatomical coordinate. Thus, a first iteration of the reformatting may be performed for a first correction of the images closer to a true anatomical coordinate. Additional iterations of the reformatting process may then be performed to fine tune the images into a coordinate system that approximates true anatomical coordinates of the patient's joint. Further, the reformatting of each bone of the joint may be performed multiple times so that the approximation of the true anatomical coordinates of the images is performed for the images of the femur and the tibia separately. As such, one or more of the operations described below may be performed any number of times to aid in reformatting the received 2D images to approximate a true anatomical coordinate image of the portions of the joint in relation to the joint replacement procedure.
Beginning in operation 602, the computing device receives the 2D images of a patient's joint or joints generated from an imaging device, as described above. In one embodiment, the computing device receives the 2D images over a network or virtual network from the imaging device or other computing device associated with the imaging device. The 2D images may be packaged into a series of images that are available to be viewed through a display of the computing device. Also, as described above, the 2D images of the joint may include a plurality of images taken along a coronal plane, an axial plane, a sagittal plane through the knee and/or other joints of the patient, or a combination of coronal, sagittal and/or axial views.
Once the 2D images of the joint are uploaded or otherwise available, the computing device or operator may conduct a reformatting stage on the 2D images in operation 604. In general, the reformatting of the 2D images is conducted on the 2D images to create a 2D image or reorient the 2D images to a coordinate system that approximates the true anatomical coordinate of the patient's joint. Thus, reformatting of the 2D images includes reorientation of the images and/or extrapolation of the joint between captured 2D images. In this manner, the 2D images may be rotated in three dimensions to reformat the images or create new images that approximate the true anatomical coordinate of the patient's joint. These images with the approximation of the true anatomical coordinate may be used to create the arthroplasty cutting jig discussed herein.
In general, the reformatting of the 2D images occurs through the placement of one or more reference points or lines within the 2D images and to reformat the images. The one or more reference points in the images provide the computing device with orientation markers in the images to aid in the process of identifying the landmarks of the patient's anatomy within the images. Through these selected landmarks and reference lines, the computing device can reformat the images into images that may be used to create a customized arthroplasty cutting jig.
In addition, reformatting the 2D images through the computing device may provide several functions to the overall customized cutting jig creation method. For example, during the reformatting stage of the customized cutting jig creation method, unusable or misaligned 2D images of the patient's joint may be noted and/or discarded. This allows for a request for additional images be taken of the patient early in the jig creation process. In addition, the imaging process may include several irregularities that may affect the effectiveness of the customized cutting jig. For example, during imaging, the patient may be oriented at an angle within the imaging device such that each of the images taken may not align with the imaging device coordinates. In this example, the resulting images may be misaligned with the global coordinates of the imaging device, making the location of the landmarks within the 2D images be similarly off axis from the global coordinate system. However, through the reformatting stage described below, one or more of the 2D images may be realigned or reoriented to compensate for the angle in which the patient was placed in the imaging device.
In another example, the 2D images, as received at the computing device, may be blurry due to movement of the patient during the imaging process. In general, the imaging procedure may take several minutes to complete, depending on the spacing between the image slices obtained. This requires that the patient remain still throughout the imagine procedure. However, it may be difficult for some patients to remain still within the imaging device during the entire procedure, due to patient discomfort due to injury or improper imaging device use, such that some movement by the patient is captured in the 2D images. Depending on the severity of the movement, the 2D images may become blurry or provide an inaccurate representation of the patient's joint. In these cases, the reformatting stage of the method illustrated in
After reformatting of the images occurs, the operator or computing device may then perform a planning stage on the 2D images, as shown in operation 606. During the planning stage, one or more landmarks on the 2D images of the patient's joint are identified and noted with electronic markers on the images in the computing device. In one embodiment, these landmarks are utilized by the computing device to create a footprint within the 2D images in which a customized cutting jig may be located in relation to the anatomy contained within the 2D images. For example, during the planning stage, the operator may indicate a medial-lateral length of a femoral cutting jig based on the 2D images of the patient's femur. As described in more detail below, the planning stage provides several reference points or landmarks in the 2D images to the computing device that may be utilized by the computing device in creating a customized cutting jig template. As also discussed below, the planning stage may be performed for separate portions of the joint, such as the femur and the tibia. This is due to the reformatting of the 2D images operation occurring on the femur and the tibia separately. In other words, the femur may be reformatted in a particular orientation while the tibia is reformatted in another orientation. As such, the planning operations may be performed for the various portions of the joint that undergo the reformatting operation.
In operation 608, the reformatted 2D images may be captured by the computing device and a stencil of the implant may be superimposed on the reformatted 2D images. For example, the reformatted femur images may be captured and a generic femur implant may be superimposed on the reformatted femur 2D images. One example of combined reformatted images and implant stencil for a patient's femur is illustrated in
Upon approval by the surgeon, the design of the cutting jig may occur. In one embodiment, the surgeon may visually determine the proper alignment of the proposed implant on the reformatted 2D images of the patient's joint and indicate an approval with an input device to a computer on which the images are being reviewed. The provided reformatted images may also include specific measurements of the implants or images, such as medial-lateral length, anterior-posterior length, angle of the implant, and the like. Also, the provided reformatted images may include a reformatted sagittal image of the joint 624,634, a reformatted coronal image of the joint 620,630, and/or a reformatted axial image of the joint 622,632.
In operation 610, the operator or computing device may then perform a template design stage on the 2D images. During the template design stage, one or more electronic markers or shapes are placed on one or more of the reformatted 2D images of the patient's joint. It should be noted that reference and discussion of 2D images in this disclosure may refer to either the original 2D images of the patient, the reformatted images of the patient as described above, or a combination of both the original and the reformatted images, unless specifically noted. In one example, the electronic shapes correspond to contact shapes of the customized cutting jigs for the femur and tibia. Thus, the electronic shapes may be placed by the operator or computing device in the 2D image in locations similar to mating locations on the patient's joint for the customized cutting jig. As such, as described in more detail below, the computing device may utilize the template design to generate a cutting or milling program from the 2D images in operation 612. The milling program, as described above, may then be provided to a CNC machine to generate the arthroplasty cutting jig. In particular, the template design features identified in the 2D images are translated into the milling program to create a cutting jig that is customized to the particular joint shown in the 2D images. As mentioned above, one or more additional reformatting stages of the 2D images may also be conducted at any point in the method illustrated in
As mentioned above, a reformatting of the 2D images of the patient's joint may be conducted to reorient in three dimensions and verify the accuracy of the images.
Beginning in operation 702, the computing device may identify the approximate center of the patient's hip in one of the 2D images. In one embodiment, as indicated in
Once a 2D image is selected, the operator then utilizes an input device (such as a mouse or a keyboard) of the computing device to locate and electronically mark the center of the hip 802 on the selected 2D image. In particular, the operator attempts to locate and electronically mark the center of the femoral head in the selected 2D image. The electronic marking of the femoral head is then stored in the computing device as a marker related to a global coordinate system within the system for orienting the 2D images. In the example of
In one embodiment, the selected hip center 802 may be an approximate center point of the femur head via visual examination of the 2D image. Thus, it is not necessary that the operator or computing device select the exact center of the femoral head. Rather, the selection of the center can be approximate. Further, in another embodiment, the computing device itself may analyze the 2D images to select an image (perhaps based on clarity of image) and electronically mark the center 802 of the femoral head. In this embodiment, the location of the femoral head is thereby at least partially automated.
In addition to locating the center of the hip, the operator or computing device may visually inspect any of the 2D images and reject the images for various reasons. For example, one constraint may be that the images must be oriented such that the femoral shaft within the image points to the bottom of the screen. If the 2D images are oriented in another direction, the images may be noted as unacceptable for the procedure and a new set of images may be conducted.
As shown in the screenshot 1000 of
Returning to
In addition to locating the center of the ankle, the operator or computing device can visually inspect the 2D images and reject the images for various reasons, such as blurriness or improper alignment. Further, as shown in the coronal 2D image 1200 in the screenshot of
Returning again to
In operation 708, the center of the knee (based on the 2D images) is determined. In one embodiment, the center of the knee is identified as the approximate center of the trochlear valley of the femur in the 2D image, which is identified in a similar manner as identifying the center of the hip and ankle, described above. Thus, an operator sitting in front of a monitor of the computing device tabs through the various coronal 2D images of the knee and selects one or more images to identify points on the image. In one embodiment, the selected 2D image shows the deepest trochlear valley when viewed from anterior aspect. In this image, the center point of the knee is the center of the trochlear valley in the selected 2D image. Similar to above, the images may also be sagittal or axial images of the knee.
Once a 2D image is selected, the operator then utilizes the input device to the computing device to locate and electronically mark the center of the knee on the selected 2D image. An example of the location of the knee center 1302 is indicated in the 2D coronal image 1300 of the screenshot of
At this point in the process, the computing device may determine whether the 2D images are of the patient's right leg to the patient's left leg. However, the 2D images are still oriented in the image machine-defined coordinate system. To begin a first reformatting of the 2D images into a coordinate system that approximates the true anatomical coordinate system of the patient's joint, additional operations may be performed. For example, in operation 710, a femur distal line of the 2D knee images knee is identified on the images. One example of a femur distal line 1402 is illustrated in the coronal 2D image of the patient's knee in the screenshot 1400 of
In operation 712, the operator or computing device determines the 2D image with the highest point of the tibia spine and identifies the highest point in the 2D image. In one embodiment, the operator sitting in front of the monitor tabs through the set of coronal 2D images of the knee and selects one or more images that shows the tibia spine with the highest point. Once a 2D image is selected, the operator then utilizes the input device to the computing device to locate and electronically mark the highest point of the tibia spine. An example of the electronic marker located at the highest tibia spine point 1502 is shown in the 2D coronal image of the knee in the screenshot 1500 of
In operation 714, the operator or computing device selects a 2D image from the set of images and identifies the anterior edge of the tibia. In particular, the anterior edge of the tibia may be observed in one of a series of coronal 2D images by scrolling. Thus, the operator sitting in front of the monitor tabs through the various coronal 2D images of the knee and selects a 2D image closest to the anterior edge of the tibia. Once a 2D image is selected, the operator then utilizes the input device to locate and electronically mark the anterior tibia edge. An example of the electronic marker located at the highest tibia spine point 1602 is shown in the 2D coronal image of the knee in the screenshot 1600 of
Continuing the reformatting of the 2D images, the operator or computing device identifies the fibula in operation 716. Similar to the above, the operator tabs through the various 2D images of the knee and selects one or more coronal images that show the fibula of the patient. Once a 2D image is selected, the operator then utilizes the input device to the computing device to locate and electronically mark the fibula in the image. An example of the electronic marker identifying the fibula 1702 in the image is shown in the 2D coronal image of the knee in the screenshot 1700 of
In operation 718, the operator or computing device identifies a tibia plateau surface line in at least one of the 2D images. One particular example an identification of the tibia plateau surface line 1802 is shown in the 2D coronal image of the knee in the screenshot 1800 of
In operation 720, the operator or computer device identifies the femoral cortical bone exterior line in one or more of the 2D images. One example of a femoral cortical bone exterior shaft line 1902 is shown in the 2D coronal image of the knee in the screenshot 1900 of
The operator then utilizing the input device, electronically draws a line along the femoral cortical bone exterior line identified in the selected 2D image. In general, the femoral cortical bone exterior line follows the exterior of the femoral cortical bone along the shaft of the femur. In this manner, a line that indicates a straight line along the femoral cortical bone exterior shaft line is represented on the 2D image. As should be appreciated, the femoral cortical bone exterior shaft line 1902 may indicate an orientation angle of the patient during the imaging process. For example, the exterior cortical bone of the femoral shaft provides an indication of the medial-lateral angle at which the patient was oriented during the imaging process. As such, this angle may be noted by the computing device for re-orienting the 2D images and ensure a proper customized cutting guide. Further, the line along the femoral cortical bone exterior may be adjusted by the operator to align best with the femoral line in the 2D image.
The operator or computer device may also identify an interior-exterior rotation angle of the femur in one or more of the 2D images in operation 722. For this operation, a series of axial images of the knee may be employed, such as the axial 2D image shown in the screenshot 2000 of
The operator then utilizing the input device, electronically draws a line 2002 from the most posterior location of one femoral condyle to the most posterior location of the other femoral condyle in the 2D axial image of the knee. For example, in the 2D image shown in
Finally, in operation 724, the operator or computing device utilizes one or more of the electronic markers and/or lines determined above to reformat the series of 2D images along a coordinate system that more closely approximates a true anatomical coordinate system for the patient based on the 2D images. In general, the reformatting of the images may include reorientation of the images and/or extrapolation of data from between image slices. In this manner, the images are reformatted in three dimensions to approximate the true anatomical coordinate system. For example, based on the femoral cortical bone exterior shaft line 1902, the computing device determines an angle at which the patient was placed in the imaging device thereby angling each of the generated 2D images. Thus, from the information entered into the computing device above, each of the 2D images in the set of images may be reformatted to account for the angle of the images obtained during imaging. Similarly, the femur distal line 1402 may provide other angle information about the 2D images. The reference lines and points identified on the 2D images through the operations described above may or may not be utilized by the computing device to reformat the 2D images to account for imaging errors, such as patient movement and placement angle during the imaging process. In general, any of the reference lines and points identified on the 2D images may be considered by the computing device when reformatting the 2D images. In one embodiment, the computing device utilizes all of the points and lines indicated above. In other embodiments, one or more of the lines or points may be dismissed or not considered when reformatting the 2D images. In some circumstances, such reformatting may adjust for an imaging angle of over 3 degrees from the true anatomical coordinate axis of the patient to an imaging angle of less than 2 degrees from the true anatomical coordinate axis.
After the 2D images are reformatted, a pre-planning stage of the 2D images may be performed by the operator or computing device. In general, the pre-planning stage results in a further refinement of the reformatting of the 2D images discussed above. In other words, the pre-planning stage reformats the 2D images even further to the true anatomical coordinate axis of the patient. After pre-planning, the resulting 2D reformatted images may be used during a jig design phase, discussed in more detail below. Also, many of the reference lines and/or boxes placed in the 2D images and discussed below reference non-damaged portions of the patient's joint to provide a more accurate placement on the images. By utilizing the non-damaged portion of the joint (rather than the arthritic or damaged portion), a cleaner location in the image of the reference points, lines, and boxes may be achieved. This is discussed in more detail throughout the description of the flowcharts of
Similar to the operations described above in relation to the method of
Beginning in operation 2102, the operator or computing device may identify the anterior cortex point of the femur in one of the 2D images. The anterior cortex point 2202 of the femur is the location on the femur, as seen in the sagittal image of the screenshot 2200 illustrated in
In one embodiment, the anterior cortex point 2202 is utilized by the computing device as an outer limit of the template for the customized cutting guide. In particular, the customized cutting guide may not extend past the anterior cortex point 2202 of the femur to avoid the cutting guide resting or mating with the femur on the femur shaft. Implants that mate with the femur on the femoral shaft may not be as stable as those implants that are limited to mating on the femoral head. Thus, in this example, the anterior cortex point 2202 provides an outer limit for the implant through which the cutting guide provides the location on the patient's femur.
Returning to
In operation 2106, the operator or computing device defines a distal reference box for the femur in the 2D images. In particular, the operator sitting in front of a monitor of the computing device selects one or more images to define a reference box. In one example, the 2D image is a coronal image near the posterior edge of the femur showing the femoral condyles. Additionally, the computing device provides a reference box for placement within the 2D image. For example, the coronal 2D image shown in the screenshot 2400 of
Further, in one embodiment, more than one 2D image may be utilized and/or selected when determining the distal reference guide. For example, a 2D image slice that is near the posterior end of the condyle (when viewing the axial image slices, an image slice near the bottom of the illustrated condyles) may be selected when adjusting the reference box 2402 angle and the two vertical internal definition lines 2404, 2406 near the edges of the inner notch between the femoral condyles. An image slice closer to the middle of the condyles when viewing the axial image slices, such as the screenshot 2500 image in
In operation 2108, the operator or computing device defines distal condyle points in at least one of the 2D images. Similar to above, an operator sitting in front of a monitor of the computing device selects one or more images and, utilizing the input device, provides an electronic indicator point at the bottom edge of the femoral condyles. In one embodiment, the distal condyle points are marked on a coronal image slice, such as shown in the coronal 2D image of the screenshot 2600 in
Similarly, in operation 2110, the operator or computing device may define an inflection point line in at least one of the 2D images. In particular, an operator sitting in front of a monitor of the computing device selects one or more images (such as a sagittal image) and, utilizing the input device, provides an electronic indicator point at the inflection point, or the location on the femur where there is a sudden change in the slope of the bone surface. Then, in an axial view that corresponds to the noted inflection point, the operator may orient a straight line along the anatomy of the knee. For example, as shown in the 2D image of the screenshot 2700 of
In one embodiment, the straight line reference 2702 is located along a rotation of axis line 2704 of the femoral notch and the condyles of the femur. In particular, the rotation of axis 2704 may be located at the inflection point of the posterior portion of the knee, at the base of the trochlear groove. This axis of rotation 2704 is seen in the sagittal view of the femur in
Continuing on to operation 2112, the operator or computing device defines an internal rotation/external rotation (IR/ER) box for the femur in the 2D images. In particular, the operator sitting in front of a monitor of the computing device selects one or more images, such as an axial image slice located near the posterior edge of the femoral condyles. In this image slice, the reference box appears on the computing device screen. In the example illustrated the 2D image in the screenshot 2800 in
Although additional modifications to the reference box 2802 may be conducted with reference to the selected 2D image, in one embodiment, one or more additional 2D images are selected to which the reference box is manipulated. For example, the operator may select another axial image slice located near the anterior edge of the patient's knee for further refinement of the reference box 2802. With this image selected, the operator may orient the upper border of the reference box 2802 to align with the highest point (most anterior point) in the 2D image. One example of the modification of the reference box 2802 manipulated in this manner to define the upper boundary of the box is shown in the 2D image in the screenshot 2808 of
Using the same or a different image slice, the operator may utilize the reference box 2802 to indicate the center of the trochlear groove of the knee. In particular and shown in the image of the screenshot 2810 of
Through the operations of
The planning stage of the 2D images may also include a planning stage for the tibia portion of the patient's knee.
Similar to the operations described above in relation to the method of
Beginning in operation 2902, the operator or computing device may identify the tibia spine center in one of the 2D images. In particular, an operator sitting in front of a monitor of the computing device tabs through the various coronal 2D images to select one where it appears the peak and valley feature of the tibia is present. One example of such a coronal 2D image is illustrated in the screenshot 3000 in
In one embodiment, the location of the u-shaped reference marker 3002, such as that shown in
Returning to
In operation 2906, the operator or computing device defines the highest fibular feature in the 2D images. In particular, an operator sitting in front of a monitor of the computing device tabs through the set of 2D coronal images and selects the one or more images that includes the highest fibula feature. Then, utilizing the input device, the operator places a location marker on the 2D image corresponding to or approximating the highest fibula feature in the 2D images. One such position 3202 is shown in the image of the screenshot 3200 of
In operation 2908, the operator or computing device defines a tibia slope in the 2D images. In particular, the operator sitting in front of a monitor of the computing device selects one or more 2D sagittal images of the knee. As shown in the screenshot 3300 of
In operation 2206, the operator or computing device defines a tibia coronal balance reference box for the tibia in the 2D images. In particular, the operator sitting in front of a monitor of the computing device selects one or more 2D coronal images of the tibia. In one embodiment, the selected 2D image includes the highest tibia spine feature. Additionally, the computing device provides a reference box for placement within the 2D image. For example, the 2D image shown in the screenshot 3400 in
The user may also adjust, utilizing the input device, the horizontal internal definition line 3406 of the reference box 3402, as shown in the screenshot 3412 of
Continuing on to operation 2912, the operator or computing device defines an internal rotation/external rotation (IR/ER) reference box for the tibia in the 2D images. In particular, the operator sitting in front of a monitor of the computing device selects one or more images, such as an axial image slice located near the anterior wall of the tibia. In this image slice, a reference box appears on the computing device screen. In the example image illustrated in the screenshot 3500 of
Although additional modifications to the reference box 3502 may be conducted with reference to the selected 2D image, in one embodiment, one or more additional 2D images are selected to which the reference box is manipulated. For example, the operator may select an axial image slice located near the anterior edge of the patient's tibia for to position the upper border of the reference box 3502 and select another axial image near the posterior edge of the patient's tibia to position the lower border. In general, any number of image slices located within the series of 2D image slices may be utilized to position the reference box 3502.
Additionally, the operator may select an axial 2D image at or near the center of the tibia for additional positioning of the borders and reference lines of the reference box 3502. With the axial 2D image slice selected, the operator, utilizing the input device, positions the left border of the reference box 3502 to a position slightly inside the left interior cortical bone of the tibia in the image. Similarly, the right border of the reference box 3502 is a position slightly inside the right interior cortical bone of the tibia in the image. One example of the positioning of the right and left borders of the reference box 3502 is shown in the screenshot 3510 of
Using the same or a different image slice, the operator may utilize the reference box 3502 to rotate the reference box to align the box with spine feature of the tibia. In particular and shown in
Through the operations of
With the completion of the reformatting stage and the planning stage, the operator or computing device may begin the template design phase for the arthroplasty cutting jigs. In particular, the information determined in the reformatting stage and the planning stage may be utilized by the computing device when generating the templates for the cutting jigs. Further, the operator or computing device may perform one or more of the operations illustrated in
Similar to the operations described above, the operations of the method of
Beginning in operation 3602, the operator or computing device may place an anterior trochlear groove circular shape in one of the 2D images. As explained in more detail below, this shape corresponds to a circular mating surface of a customized femoral cutting jig that contacts the femur in the anterior portion of the trochlear groove. Thus, the placement of the circular shape in the 2D images may be translated to a milling program that creates the same or a similar shape in a customized femoral cutting guide for use in an arthroplasty procedure. In one embodiment, an operator sitting in front of a monitor of the computing device tabs through the various axial 2D images of the patient's knee to select an image for placement of the trochlear groove circular shape. In one particular example, the selected image is a coronal image slice lying between the anterior cortex point of the femur and the bottom or valley of the trochlear groove identified above in the planning stage. Once the image is selected, the computing device provides a circular shape on the 2D image that is adjustable by the operator. An example of the circular shape 3702 provided in the coronal 2D image is shown in the screenshot 3700 of
In operation 3604, the operator or computing device may locate posterior contacts of a trochlear groove trapezoidal mating shape in one of the 2D images. As explained in more detail below, this shape corresponds to a pair of surface contacts of a customized femoral cutting jig that contact the patient's femur on the condyles. Thus, the location of the posterior contacts of a trochlear groove trapezoidal mating shape in the 2D images may be translated to a milling program that creates a mating surface on a customized femoral cutting jig for use in an arthroplasty procedure that corresponds to the placement of the posterior contacts. In this manner, the posterior contacts of a trochlear groove trapezoidal mating shape is customized to the patient's femur as captured in the 2D images of the joint.
In one embodiment, as shown in the screenshot 3800 of
To adjust the length and placement of the bottom edge 3804 of the trochlear groove trapezoidal shape 3802, a pair of adjustable straight line features may be provided in the coronal image that corresponds to the selected axial image. As shown in the screen shot 3820 of the corresponding coronal image in
In a similar manner, the operator or computing device may locate anterior contacts of a trochlear groove trapezoidal mating shape in one of the 2D images in operation 3606. The location of the anterior contacts in the 2D images may also be translated to a milling program that creates a mating surface on a customized femoral cutting jig for use in an arthroplasty procedure that corresponds to the placement of the anterior contacts. In this manner, the anterior contacts of a trochlear groove trapezoidal mating shape is customized to the patient's femur as captured in the 2D images of the joint.
As similar to above, the computing device may provide an axial image (image 3800 as seen in
In addition, the right straight line feature 3904 may be placed to account for the location of the PCL in the 2D image. More particularly, the right straight line feature 3904 may be positioned slightly below the PCL location to ensure that the cutting guide mates with the femur and not on the PCL. The horizontal line of the right straight line feature 3904 may indicate the upper bound of the straight line feature and may be placed below the PCL shown in the 2D image. As should be appreciated, it is not necessary that the contact points of the upper edge of the trapezoid be aligned. Rather, the contact of the upper edge of the trapezoid on the right condyle may not be aligned with the contact of the upper edge of the trapezoid on the left condyle. This is shown in
In operation 3608, the operator or computing device may place a pair of trochlear groove posterior circle shapes in one of the 2D images. As explained in more detail below, these shapes correspond to the posterior trochlear groove circle mating surfaces of a customized femoral cutting jig. Thus, the location of the pair of trochlear groove posterior circle shapes in the 2D image may be translated to a milling program that creates a mating surface on a customized femoral cutting jig for use in an arthroplasty procedure that corresponds to the placement of the posterior circles. In this manner, the pair of trochlear groove posterior circle shapes is customized to the patient's femur as captured in the 2D images of the joint.
In one embodiment, the computing device may provide an axial image to the operator that includes the trapezoidal shape discussed above. In addition, a coronal view corresponding to a position near the bottom edge of the trapezoidal shape may also be provided to the operator on the computing device monitor. Within the coronal view, the computing device provides a pair of trochlear groove posterior circle shapes within the image. Similar to the circular shape described above, the pair of trochlear groove posterior circle shapes within the 2D image may be adjustable by the operator. In particular, the operator utilizes the input device to the computing device to move the pair of trochlear groove posterior circle shapes within the 2D image. In particular, the circle shape is placed in the 2D image such that the circle contacts the two femoral condyles within the trochlear groove. As shown in the screenshot 4000 of the coronal image in
In operation 3610, the operator or computing device may place a mid-trochlear groove circle shape in one of the 2D images. This shape corresponds to a circular mating surface of a customized femoral cutting jig that contacts the femur in the middle portion of the trochlear groove when mated with the femur. Thus, the location of the mid-trochlear groove circle shape in the 2D image may be translated to a milling program that creates a mating surface on a customized femoral cutting jig for use in an arthroplasty procedure that corresponds to the placement of the mid-trochlear circle shape. In this manner, the mid-trochlear groove circle shape is customized to the patient's femur as captured in the 2D images of the joint.
In one embodiment, the computing device may provide an axial image to the operator that is near the center axis of the femur shaft. In addition, a coronal view corresponding to the selected axial image is provided to the operator. Within the coronal view, the computing device provides a circular shape. An example of the circular shape 4102 provided in the image is shown in screenshot 4100 in
In operation 3612, the operator or computing device may place a pair of rectangle shapes in one of the 2D images. As explained in more detail below, this shape corresponds to a pair of rectangular shaped mating surfaces of a customized femoral cutting jig. Thus, the location of the rectangular shapes in the 2D image may be translated to a milling program that creates a mating surface on a customized femoral cutting jig for use in an arthroplasty procedure that corresponds to the placement of the rectangular shapes in the 2D image. In this manner, the rectangular shapes are customized to the patient's femur as captured in the 2D images of the joint.
In one embodiment, the computing device provides an axial image to the operator that is the same or similar to the axial image for the anterior trochlear groove circle shape discussed above. In addition, a coronal view corresponding to the selected axial image is provided to the operator. Within the coronal view, the computing device provides a pair of rectangular shapes. An example of the rectangular shapes 4202, 4204 provided in the image is shown in the screenshot 4200 of
In a similar manner, a template for the customized tibia jig may also be created. Thus, the operator or computing device may perform one or more of the operations illustrated in
Similar to the operations described above, the operations of the method of
Beginning in operation 4302, the operator may verify that the bottom of the template of the customized cutting jig sits above the spine feature of the tibia. In particular, the computing device may provide an indicator, such as a reference box, in the 2D image that shows the location of the bottom of the template of the customized guide in relation to the 2D images. The operator may then tab through the set of coronal images that show the tibia to determine if the bottom edge of the reference box remains above the spine feature of the tibia. If an interference with the spine feature is detected on one or more of the image slices, the operator may move the reference box up in one or more of the 2D images to avoid interference with the spine.
In operation 4304, the operator or computing device may place a pair of circular shapes on the anterior surface of the tibia in one of the 2D images. These shapes correspond to the anterior surface circular contact surfaces of a customized femoral cutting guide. As such, the location of the pair of circular shapes on the anterior surface of the tibia in the 2D image may be translated to a milling program that creates a mating surface on a customized tibia cutting jig for use in an arthroplasty procedure that corresponds to the placement of the circular shapes. In this manner, the pair of circular shapes on the anterior surface of the tibia is customized to the patient's tibia as captured in the 2D images of the joint.
In one embodiment, the operator or computing device may select a 2D axial image of the tibia that is located slightly below the proposed resection line through the tibia. Within the axial image, the computing device provides a pair of circular shapes on the anterior surface of the tibia. Further, the pair of circular shapes on the anterior surface of the tibia within the 2D image may be adjustable by the operator. In particular, the operator utilizes the input device to the computing device to move the pair of circular shapes on the anterior right side surface of the tibia within the 2D image. One example of the position of the pair of circular shapes 4402, 4404 on the anterior surface of the tibia is shown in the screenshot 4400 of
In one embodiment, the pair of circular shapes 4402, 4404 on the anterior surface of the tibia may include a corresponding straight line reference 4406, 4408 that moves with the particular circular shape when the circular shape is moved by the operator. For example, when one of the circular shapes 4402, 4404 is moved to the right in the 2D image, the corresponding straight line reference 4406, 4408 also moves to the right. In this embodiment, the straight line references 4406, 4408 correspond to a potential drill hole of the tibia cutting jig. The location of the drill hole in relation to the circular shape is determined by the computing device through the general shape of the tibia cutting jig blank. In other words, the location of the drill hole in relation to the circular shape 4402, 4404 may be common among the cutting jig blanks and is known by the computing device. Thus, in this embodiment, the placement of the pair of circular shapes 4402, 4404 on the anterior surface of the tibia may be made in relation to the corresponding drill hole locations.
In operation 4306, the operator or computing device may place an anterior medial circular shape in one of the tibia 2D images. As explained in more detail below, this shape corresponds to the anterior medial circular mating surface of a customized tibia cutting guide. Thus, the location of the anterior medial circular shape in the 2D image may be translated to a milling program that creates a mating surface on a customized tibia cutting jig for use in an arthroplasty procedure that corresponds to the placement of the anterior medial circular shape. In this manner, the anterior medial circular shape is customized to the patient's tibia as captured in the 2D images of the joint.
In one embodiment, the operator or computing device selects an axial image of the tibia from which a coronal image slice is selected. In one particular embodiment, the coronal image is selected from an area between the center and the lower edge of the lowest circular shape on the anterior surface of the tibia in the axial image discussed above. From this selection in the axial image, a coronal view corresponding to the selected axial image is provided to the operator. Within the coronal view, the computing device provides a circular shape. An example of the circular shape 4502 is provided in the coronal image is shown in screenshot 4500 of
In operation 4308, the operator or computing device may place an anterior lateral circular shape in one of the tibia 2D images. As explained in more detail below, this shape corresponds to the anterior lateral circular mating surface of a customized tibia cutting jig. Thus, the location of the anterior lateral circular shape in the 2D image may be translated to a milling program that creates a mating surface on a customized tibia cutting jig for use in an arthroplasty procedure that corresponds to the placement of the anterior lateral circular shape. In this manner, the anterior lateral circular shape is customized to the patient's tibia as captured in the 2D images of the joint.
In one embodiment, the operator or computing device selects a sagittal image of the tibia from which a coronal image slice is selected. In one particular embodiment, the coronal image is selected from an area above the anterior slope of the tibia in the sagittal image discussed above. From this selection in the sagittal image, a coronal view corresponding to the position in the sagittal image is provided to the operator. Within the coronal view, the computing device provides a circular shape. An example of the circular shape 4602 provided in the coronal image is shown in the screenshot 4600 of
In operation 4310, the operator or computing device may place a posterior medial circular shape in one of the tibia 2D images. As explained in more detail below, this shape corresponds to the posterior medial circular mating surface of a customized tibia cutting jig. Thus, the location of the posterior medial circular shape in the 2D image may be translated to a milling program that creates a mating surface on a customized tibia cutting jig for use in an arthroplasty procedure that corresponds to the placement of the posterior medial circular shape. In this manner, the posterior medial circular shape is customized to the patient's tibia as captured in the 2D images of the joint.
In one embodiment, the operator or computing device selects an axial image of the tibia from which a coronal image slice is selected. In one particular embodiment, the coronal image is selected from a posterior medial area spaced apart from the anterior medial circle position determined above. From this selection in the axial image, a coronal view corresponding to the position in the axial image is provided to the operator. Within the coronal view, the computing device provides a circular shape. An example of the circular shape 4702 provided in the coronal image is shown in the screenshot 4700 of
Similarly, in operation 4312, the operator or computing device may place a posterior lateral circular shape in one of the tibia 2D images. As explained in more detail below, this shape corresponds to the posterior lateral circular mating surface of a customized tibia cutting jig. Thus, the location of the posterior lateral circular shape in the 2D image may be translated to a milling program that creates a mating surface on a customized tibia cutting jig for use in an arthroplasty procedure that corresponds to the placement of the posterior lateral circular shape. In this manner, the posterior lateral circular shape is customized to the patient's tibia as captured in the 2D images of the joint.
In one embodiment, the operator or computing device selects an axial image of the tibia from which a coronal image slice is selected. In one embodiment, the axial image may be the same or similar image selected in operation 4310 discussed above. From this selection in the axial image, a coronal view corresponding to the position in the axial image is provided to the operator. Within the coronal view, the computing device provides a circular shape. An example of the circular shape 4802 provided in the coronal image is shown in
In operation 4314, the operator or computing device may place a mid-lateral circular shape in one of the tibia 2D images. As explained in more detail below, this shape corresponds to the mid-lateral circular mating surface feature of a customized tibia cutting jig. Thus, the location of the mid-lateral circular shape in the 2D image may be translated to a milling program that creates a mating surface on a customized tibia cutting jig for use in an arthroplasty procedure that corresponds to the placement of the mid-lateral circular shape. In this manner, the mid-lateral circular shape is customized to the patient's tibia as captured in the 2D images of the joint.
In one embodiment, the operator or computing device selects an axial image of the tibia from which a coronal image slice is selected. In one particular embodiment, the coronal image is selected from a position slightly below the anterior lateral circle position determined above. From this selection in the axial image, a coronal view corresponding to the position in the axial image is provided to the operator. Within the coronal view, the computing device provides a circular shape. An example of the circular shape 4902 provided in the coronal image is shown the screenshot 4900 in
Through the methods described above, a customized arthroplasty cutting guide or jig for a joint may be created specific to the anatomy of the patient. In particular, the methods provide for creating a customized arthroplasty cutting jig from one or more 2D images of the patient's joint. The method includes receiving the 2D images of the joint from an imaging device, reformatting the images, and creating a customized jig template from the images. In general, one or more landmarks are electronically marked on one or more of the series of 2D images of the patient's joint through a computing device. These electronic markers on the series of 2D images correspond to landmarks of the patient's joint undergoing the arthroplasty procedure. Once the template for the cutting jig is created by the computing device utilizing one or more of the electronic markers on the 2D images, a cutting or milling program is generated by the computing device. The cutting or milling program may then be provided to a milling machine to create the cutting jig corresponding to the milling program. The cutting jig is thus customized to the landmarks identified in the series of 2D images of the patient's joint.
I/O device 5030 may also include an input device (not shown), such as an alphanumeric input device, including alphanumeric and other keys for communicating information and/or command selections to the processors 5002-5006. Another type of user input device includes cursor control, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to the processors 5002-5006 and for controlling cursor movement on the display device.
System 5000 may include a dynamic storage device, referred to as main memory 5016, or a random access memory (RAM) or other computer-readable devices coupled to the processor bus 5012 for storing information and instructions to be executed by the processors 5002-5006. Main memory 5016 also may be used for storing temporary variables or other intermediate information during execution of instructions by the processors 5002-5006. System 5000 may include a read only memory (ROM) and/or other static storage device coupled to the processor bus 5012 for storing static information and instructions for the processors 5002-5006. The system set forth in
According to one embodiment, the above techniques may be performed by computer system 5000 in response to processor 5004 executing one or more sequences of one or more instructions contained in main memory 5016. These instructions may be read into main memory 5016 from another machine-readable medium, such as a storage device. Execution of the sequences of instructions contained in main memory 5016 may cause processors 5002-5006 to perform the process steps described herein. In alternative embodiments, circuitry may be used in place of or in combination with the software instructions. Thus, embodiments of the present disclosure may include both hardware and software components.
A machine readable medium includes any mechanism for storing or transmitting information in a form (e.g., software, processing application) readable by a machine (e.g., a computer). Such media may take the form of, but is not limited to, non-volatile media and volatile media. Non-volatile media includes optical or magnetic disks. Volatile media includes dynamic memory, such as main memory 5016. Common forms of machine-readable medium may include, but is not limited to, magnetic storage medium; optical storage medium (e.g., CD-ROM); magneto-optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; or other types of medium suitable for storing electronic instructions.
A femoral cutting jig conforming with various aspects of the present disclosure includes a substrate from which various jig contact points project, are otherwise supported or defined. In one possible implementation, the jig is a unified structure formed from a block of base material using a computer numerical control (CNC) machine. However, it is possible for the jig to be an assembly of various components that form the final cutting jig structure. Alternatively, the jig may be created through molding, machining, milling, forming, 3D printing, assembling, or other processes. The jig contact points are arranged and spaced such that a surgeon may press the jig onto the distal surface of the femur and the jig will be properly positioned when the jig contact points are seated on respective femoral contact points. Notably, there are a discrete number of jig contact points (e.g., 9-14) as opposed to full surfaces or far more numerous numbers of contact locations. The jig also includes a cutting guide support structure onto which may be mounted a cutting guide (CG). When the jig is seated on the femur, the jig may be pinned to the femur to properly position the cutting guide so that a resection of the femur may be performed pursuant to a total knee replacement.
Referring now to
Beginning at the trochlear groove end of the jig 20, a vertical projection 11 (
The implementation of the jig illustrated herein includes two curvilinear (e.g., partial circle or section) trochlear groove surfaces, with each surface defining two jig contact points (JCP1, JCP2 and JCP5, JCP6) configured to engage respective first and second femoral contact points (CP1 and CP2) and respective fifth and sixth contact points (CP5 and CP6) to either side of the trochlear groove 14 adjacent the respective condyles. More specifically, a first curved surface 15 defining the first jig contact point (JCP1) and the second jig contact point (JCP2). The first and second jig contact points contact respective first and second femoral contact points (CP1 and CP2). In the specific implementation illustrated, the surface 15 defines a curvilinear lip 16, which is bounded between the first and second vertical surfaces 14-1, 14-2, a third and a fourth horizontal surface, 17-1 and 17-2, and vertical surface 18. A third jig contact point JCP3 and a fourth jig contact point JCP4 are defined along a boundary between the respective horizontal surfaces 17-1/17-2 and a third vertical surface 18. The jig contact points JCP3 and JCP4 may be in the same plane as JCP1 and JCP4 (substantially parallel to the femoral axis), and contact respective femoral contact points CP3 and CP4, on the respective lateral and medial condyles adjacent the trochlear groove with points CP1 and CP2 above points CP3 and CP4, respectively on the lateral and medial condyles. Stated differently, the contact points CP3 and CP4 may be on the portions of the condyles facing each other at the trochlear groove 14, and may be on the walls of the groove itself, and the respective points CP3 and CP4 medially and laterally, respectively, CP1 and CP2.
As discussed throughout, the jig structure illustrated is a convenience of manufacturing, with the jig originally formed from a block of material and machined away to form the resulting structures. It is possible to also define a curvilinear surface 16 as a discrete planar element extending from the first substrate portion, and defining the curvilinear (arcuate) surface with contact points JCP1 and JCP2. Jig contact points JCP3 and JCP4 may be defined using a planar rectangular element, a radial planar element, or other structures. In the implementation shown, the surface 15 is machined to a smaller size relative to the 16 so that the jig contact points defined along surface 16 may contact the appropriate femur surface without unintentional contact by surface 15. Since the groove 14 descends away from the jig when positioned, the arced surface shape 15 is believed to not interfere with the groove while at the same time not requiring extensive machine time. The surface 16 may be machined to a greater extent than illustrated but such machining would require greater time and is not believed to be required for most patients. Finally, should there be contact between surface 15 and the knee, the shape is believed to allow the surgeon to press the jig into place and ensure proper contact between the jig contact points and the femur contact points.
The third vertical surface 18 bounds the first curved surface 15 and bounds the third and fourth horizontal surfaces, 17-1 and 17-2. The third vertical surface 18 is bounded on one side by a second curved surface 19 defining fifth and sixth jig contact points JCP5 and JCP6, which contact respective femoral contact points CP5 and CP6. In the specific implementation shown, the contact points are defined along a second curved surface lip 54, bounded on one side by a fourth vertical surface 21. The contact points CP5 and CP6 are on the respective lateral and medial condyles 10, 12, and posterior relative to the contact points CP1 and CP6. Stated differently, the contact points CP5 and CP6 are on the respective lateral and medial condyles or the portion of the groove 14 adjacent thereto, at the posterior region of the trochlear groove 14 adjacent the intercondylar fossa 16. As with other surfaces, projections and the likely structure illustrated is a convenience of manufacturing, with the jig originally formed from a block of material and machined away to form the resulting jig contact points JCP5 and JCP6. It is possible to also define a curvilinear surface 54 as a discrete planar element extending from the first substrate portion 48, and defining the curvilinear (arcuate) surface with contact points JCP5 and JCP6. The first curvilinear surface 16 is concentric with the second curvilinear surface 20.
As illustrated, there are six jig contact points defined to contact the respective lateral and medial condyles to either side of the trochlear groove. In the embodiment shown, there are four contact points defined along two curvilinear arcuate surfaces 16 and 54. The arcuate surfaces are defined to fit down within the space above groove with portion of the arcs touching the groove or respective condyles. The respective condyles are generally rounded and come to a peak region where the contact points CP3 and CP4 are defined and where the planar/linear surfaces 17-1, 17-2 may define the jig contact points JP3 and JP4. In this way, the jig may be placed down on the femur and the jig contact points may touch and seat against the respective femoral contact points.
A first and a second horizontal plateau projection, 22-1 and 22-2, each with an aperture, 30A and 30B defined therein, extend transversely adjacent to the fourth vertical surface 21 and are part of the first substrate, in one possible implementation. As shown in
With respect now to contact points adjacent the intercondylar fossa 16, six additional jig contact points may be defined that cooperate with the first six contact points discussed above, to secure the jig to the femur for a procedure. More particularly, first and second curvilinear quadrilaterals, 23 and 24, extend from the first substrate and are contiguous to each other. The quadrilaterals may be generally parallel the second substrate portion 50. The vertical surfaces are part of the second substrate portion. Additionally, adjacent and outward from the quadrilaterals, two curvilinear surfaces 25 and 26 project from the first substrate. Collectively, the quadrilaterals and curvilinear surfaces define jig contact points JCP7-JCP12 that contact respective femoral contact points CP7-CP12 lying on the lateral and medial condyles adjacent the intercondylar fossa 16. More specifically, as shown in
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The contact points CP1, CP2, CP3, CP4, CP5 and/or CP6 are associated with features of the trochlear groove and condyle features adjacent thereto, and the contact points CP7, CP8, CP9, CP10, CP11 and/or CP12 are associated with features of one or both of the condyles adjacent to and posterior from the intercondylar fossa. One goal of the contact points on the jig 20 is to provide an optimal position of the jig in contact with the distal femur for which lateral rotation (posterior to anterior, or anterior to posterior) of the jig relative to the lower femur, or longitudinal (sagittal) translation of the jig relative to the lower femur, or axial twisting (rotation) clockwise or counterclockwise is strongly resisted by friction. Stated differently, when the jig is properly positioned on the femur such that the jig contact points are touching the respective femoral contact points, the jig is firmly held on the femur through the intercooperation of the jig contact points to the femoral contact points. While it is possible, that a small number of the jig contact points, e.g., one or two, may not actually touch the femur due to actual femoral inconsistencies relative to the images of the femur, the jig will nonetheless be held in position.
More specifically and as illustrated in
The jig is also held against rotational movement in the axial plane or twisting or canting off the sagittal plane. For perspective, if the femoral head above and adjacent the intercondylar fossa is considered along the axis of the femur, or relatively close, the contact points JCP1, JCP3 and JCP5 cooperate with JCP8, JCP10, and JCP12 to oppose rotational forces in the counterclockwise direction with the axis as reference. Similarly, the contact points JCP2, JCP4, and JCP6 cooperate with JCP7, JCP9 and JCP11 to oppose rotational forces in the clockwise direction with the axis as reference.
Referring primarily to
As illustrated, the contact points JCP1-JCP4, may be separated from JCP5, JCP6 by between about 15 millimeters (a range of 12-18 millimeters being typical). The contact points JCP5 and JCP6 are posteriorly relative to JCP1-JCP4. The contact points JCP5 and JCP6 may be separated from JCP7 and JCP8 by about 14 millimeters (a range of 11-17 millimeters being typical). The contact points JCP7 and JCP8 posterior relative to JCP5 and JCP6. The contact points JCP9-JCP12 may be separated from JCP7 and JCP8 be about 10 millimeters (a range of 7 to 13 millimeters being typical). The contact points JCP9-JCP12 are posterior relative to JCP7 and JCP8. The dimensions are from a sagittal plane to a sagittal plane, measured transversely (posteriorly) with reference to the orientation and arrangement illustrated in
While the jig implementation illustrated includes 12 jig contact points, it is possible to provide a jig with slightly more or slightly less contact points. For example, JCP3 and JCP4 might be eliminated. In another example, JCP3 and JCP4 and/or JCP5 and JCP6 might be eliminated. In another example, JCP8 and JCP7 might be eliminated. In another example, JCP3 and JCP4, and/or JCP5 and JCP6, and JCP7 and JCP8 might be eliminated.
Additionally, it is possible to move the various points anteriorly or posteriorly relative to the positions indicated. Such movement may depend on damage to the knee being replaced, shape of the trochlear groove, shape of one or both condyles, the size of the femur, and the type of procedure being performed.
A tibial cutting jig 20 conforming with various aspects of the present disclosure includes a substrate from which various jig contact points (JCPm) project, are otherwise supported or defined. In one possible implementation, the jig 20 is a unified structure formed from a block of base material using a computer numerical control (CNC) machine. However, it is possible for the jig to be an assembly of various components to form the final cutting jig structure. Alternatively, the jig may be created through molding, machining, milling, forming, 3D printing, assembling, or other processes. The term “substrate” as used herein is meant to refer to a base structure upon which the various jig contact points and jig contact point supporting structures are provided or otherwise supported, and by which the relative positioning of the various jig contact points are maintained. As mentioned, the jig may be a unified structure and hence the substrate and jig contact points are formed from the same material and thus the relative positioning of the jig contact points is naturally maintained. Other processes, such as milling a base material or forming a jig in a mold, would provide a similar unified structure. It is not necessary, however, that the jig be unified structure in which case the substrate may be a frame or other structure or assembly on which various jig contact point defining structures are attached or otherwise associated.
The jig contact points are arranged and spaced such that a surgeon may press the jig onto the proximal surface of the tibia and the jig will be properly positioned when the jig contact points are seated on respective tibial contact points (TCPm). Notably, there are a discrete number of jig contact points (e.g., 5-8) as opposed to full surfaces or far more numerous numbers of contact locations. The jig also includes a cutting guide support structure onto which the cutting guide 31 may be mounted. When the jig 20 is seated on the tibia 10, the jig may be pinned to the tibia and properly position the cutting guide so that a resection of the tibia may be performed pursuant to a total knee replacement, for example.
The tibia plateau 11 at a proximal surface of the tibia 10, shown in
Five curvilinear surfaces, 21, 22, 23, 24, 25, project from a first substrate surface 26 of the jig 20 to provide jig contact points, JCPm (m=1, 2, . . . , 5) corresponding to the respective tibia contact points, TCPm (m=1, 2, . . . , 5) (
As shown, some of the curvilinear surfaces are formed of a plurality of curvilinear surfaces (e.g., sectors) arranged proximate each other and forming radial steps of increasing (or decreasing) radiuses depending on perspective. The collection of radial steps of any given projection provides greater structural integrity of the projection due to the thickness of the projection. The contact point for any given projection, however, may be defined along only one of the radial steps and preferably the largest radius step in the example jig implementation shown here. Moreover, it is possible to provide a larger projection, without any steps, one or more steps of differing thicknesses, depending on the particular contact point being defined as well as the contour and surface shape of the tibia at the tibial contact point for the corresponding jig contact point. The use of steps, however, helps ensure that any of the contact points touch the bone while also maintaining structural support for the projection due to the increasing thickness at and below the steps.
A linear sight projection 32, projecting from the substrate surface 26 and located between the jig contact points, JCP1, JCP2 and JCP3, and the jig contact points, JCP4 and JCP5, serves to align itself with the spine direction D-D defined by the spine aperture (
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Depending on the implementation, it may be preferable that no corner point, such as a jig contact point, be sharp or otherwise have a high degree of sharpness such as is often associated with a true “point”. Rather, a contact point may have an associated point segment that is at least about 0.3 mm in actual size or larger up to and including a line, in one possible implementation. The incorporation of this constraint will help ensure that, for example, a jig contact point will have adequate frictional contact such that the contact point will not slip or otherwise move relative to a region on the tibia, but at the same time the contact point will not penetrate or pierce any soft tissue on the portion of the tibia being contacted and hence possibly distort the fit of the jig to the tibia. It is less of a concern about damaging the tibia as the portion of the tibia being contacted is likely to be removed (resected) and replaced with a prosthetic implant. Notably, where a straight line segment from a square, rectangle, triangle or trapezoid is used as the contact point defining structure, and a corner of such structure is not the contact point, the area along the straight line segment at which contact is made, is considered a contact point. Moreover, in such an implementation, the straight line segment may have a rounded or otherwise non-knife edge cross section, particularly at the area where the surface is intended to contact the femur.
In the implementation shown, the curvilinear surfaces 21, 22, and 23 each comprise a plurality of semi-circular portions, each of slightly differing radius (lesser radius). The same situation is also present with the surfaces 24 and 25, and 17 and 28. In each case, the largest radius portion provides the jig contact point and the adjacent portions (steps) of lesser radius enhance the structural integrity of the projection but are not meant to contact the tibia, although some unintended contact is possible. Accordingly, the decreasing radius portions are positioned on the side of the projection best suited to not interfere with the tibia or the jig contact point. For example, with respect to surfaces 24 and 25, the decreasing radius portions of each surface face each respective surface. The tibia in the area where the jig contacts the tibia at tibia contacts points TCP4 and TCP5, however, is concave. Accordingly, the radiuses do not track the slope of the tibia in the contact area, but instead are counter to the slope, thereby minimizing the likelihood of inadvertent contact. In contrast, if the decreasing radius portions were placed on the opposite sides shown, the decreasing radiuses would be similar to the upward slope of the tibia in these areas and while they may not contact the tibia, the decreasing radiuses would have less of a distance and thus more possibly contact the tibia.
The curvilinear projections illustrated may define sectors with the contact point defined along the edge of the sector. In the implementation illustrated, the projections extend from the substrate as discrete planar elements with the surface intended to contact the tibia defining the sector. As discussed, the edge may define a stepped structure in one possible example. Moreover, the edge may define a relatively narrow flat edge so as not to define a sharp edge. Other suitable shapes may be used to define the contact points. For example, a conical projection with the contact point defined as the tip area of the cone may extend from the substrate. In another example, a post may extend from the substrate, with the tip area of the post defining the jig contact point. The tip may be rounded, flat, beveled, etc. Other planar shapes, such as those illustrated in
The contact points JCP1, JCP2, JCP3, JCP4 and JCP5 are associated with features of the tibia plateau 11, and the jig contact points JCP6 and JCP7 are associated with features of the shaft. One goal of the contact points on the jig 20 is to provide an optimal position of the jig in contact with the proximal tibia, for which lateral rotation (posterior to anterior, or anterior to posterior) of the jig relative to the tibia, or longitudinal (sagittal) translation of the jig relative to the tibia, or axial twisting (rotation) clockwise or counterclockwise, is resisted by friction caused by contact between the jig and the tibia at the contact point. Stated differently, when the jig is properly positioned on the tibia such that the jig contact points are touching the respective tibial contact points and firmly seated there by a surgeon, the jig is firmly held in the correct orientation on the tibia through the interoperation of the jig contact points to the tibia contact points. While it is possible that a small number of the jig contact points, e.g., one or two, may not actually touch the tibia due to actual tibial inconsistencies relative to the images of the tibia, the jig will nonetheless be held in position.
As illustrated in
Although the jig implementation illustrated includes seven (7) jig contact points, it is possible to provide a jig with slightly more or slightly fewer contact points. For example, JCP2 and JCP3 might be eliminated, and replaced with a contact point lying therebetween, and perhaps with a larger cross section, while still abutting the articular surface adjacent to the lateral intercondylar tubercle 14A. In another example, JCP1 may be eliminated. In yet another example, JCP4 and JCP5 may be eliminated, and replaced with a contact point lying therebetween, and perhaps with a larger cross section, while still abutting the articular surface adjacent to the medial intercondylar tubercle 14B. In another example, JCP2 and/or JCP4 may be eliminated. While the jig implementation illustrated includes seven jig contact points, it is possible to provide a jig with slightly more or slightly less contact points. For example, JCP2 might be eliminated. In another example, JCP1 may be shifted medially, and JCP4 eliminated. Additionally, it is possible to move the various points anteriorly or posteriorly relative to the positions indicated. Such movement may depend on damage to the knee being replaced, shape of the trochlear groove, shape of one or both condyles, the size of the tibia, and the type of procedure being performed.
Additionally, it is possible to move the various contact points anteriorly, posteriorly, laterally and/or medially relative to the positions indicated. Such movement may depend on damage to the knee being replaced, shape of the trochlear groove, shape of one or both condyles, the size of the tibia, and the type of procedure being performed. Additionally, one of more points may be defined below the tibial plateau at different locations than TCP 6 and TCP 7. For example, points may be positioned to engage the anterior surface, below the plateau, of the lateral tibial condyle.
Providing a different perspective as illustrated in
The jig is also held against rotational movement in the axial plane or twisting or canting off the sagittal plane. For perspective, if the tibial plateau region generally between the tubercles is considered along the axis of the tibia, or relatively close, the contact points JCP1 and JCP2 cooperate with JCP4 to oppose rotational forces in the clockwise direction with the axis as reference. Similarly, the contact point JCP5 cooperates with JCP1 to oppose rotational forces in the counter clockwise direction with the axis as reference. JCP6 and JCP7 also work in conjunction with the other contact points to help prohibit rotation, and to prevent the jig from rotating off the tibia coronally.
Referring primarily to
The various features discussed and shown herein are but one way to create a jig defining the various jig contact points of interest. In the example shown, the CNC machine tool bits and other cutting mechanisms influence the jig shapes. The various surfaces and jig features, on which the jig contact points are defined, are thus defined in part by requirements of the CNC machine. If the jig were formed in another way, such as through 3D printing, molding, and the like, the jig contact point features and overall jig shape may be different than illustrated although the position and relative location of the jig contact points, depending on the patient, would be substantially the same regardless of the jig manufacturing technique employed.
The embodiment shown contemplates a cut plane guide that is separately pinned to the femur so that the jig may be removed prior to resection. This embodiment contemplates the jig being of possibly different material (e.g., a surgical grade polymer) rather than stainless steel or the like. It is possible, however, to fabricate the cutting guide into the body of the jig and form a unified structure where the entirety of the jig is pinned to the femur and stays in place during the resectioning procedure. It is also possible, depending on the material used for the jig, to place a liner within the cut slot of the cutting guide, where the liner is stainless steel such that the saw will not cut the slot during the back and forth sawing action. It is also possible for the slot to be integrated in the jig directly, in which case the cut plane guide will be a part of the jig.
The embodiment discussed above contemplates the use of pins to secure the jig and the cutting plane guide in place. It is possible, however, to use other forms of anchors such as screws or combinations of screws and pins. It is also possible, in the case of pins, to use some relatively small (smaller than threads of a screw) of some form of abrasive surface—e.g., annular ridges, roughing, or the like along some or all of the pin shaft, to ensure the pins stay in place and therefore holds the respective jig and/or cutting plane guide in place. Moreover, the jig is shown as defining a plurality of apertures, along with respective bosses, to receive such anchors. It is possible, however, to have the apertures defined in separate structures attached to or otherwise associate with the jig or to secure the jig to the femur in some other way, or to simply hold it in place while the cut plane guide is secured to the femur.
It should be noted that the flowcharts above are illustrative only. Alternative embodiments of the present invention may add operations, omit operations, or change the order of operations without affecting the spirit and scope of the present invention. The foregoing merely illustrates the principles of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustrations only and are not intended to limit the scope of the present invention. References to details of particular embodiments are not intended to limit the scope of the invention.
Claims
1. A method for creating a cutting jig for an arthroplasty procedure, the method comprising:
- receiving a plurality of two-dimensional images of a patient's joint the subject of the arthroplasty procedure;
- reformatting the two-dimensional images to approximate a true anatomical coordinate of the patient's joint;
- locating a plurality of mating shapes within the reformatted plurality of two-dimensional images of the patient's joint, the plurality of mating shapes corresponding to a plurality of mating shapes of a cutting jig for use during the arthroplasty procedure;
- generating a milling program based at least on the placement of the mating shapes within the reformatted plurality of two-dimensional images of the patient's joint; and
- milling the cutting jig based at least on the milling program.
2. The method of claim 1 further comprising:
- generating the plurality of two-dimensional images of a patient's joint the subject of the arthroplasty procedure utilizing a magnetic-resonance imaging machine.
3. The method of claim 1 wherein reformatting the two-dimensional images comprises:
- identifying one or more landmarks on the plurality of two-dimensional images of a patient's joint; and
- reorienting the plurality of two-dimensional images of a patient's joint based at least on the one or more landmarks.
4. The method of claim 1 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images comprises indicating a position of a first circular mating shape of a femoral portion of the cutting jig such that the first circular mating shape of the femoral portion contacts at least one femoral condyle within an anterior trochlear groove of the patient's joint as illustrated in a first one of the plurality of two-dimensional images of the patient's joint.
5. The method of claim 4 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- indicating a position of a first portion of a trapezoidal mating shape of the femoral portion of the cutting jig such that the first portion of a trapezoidal mating shape tangentially contacts an inner surface of a first condyle of the patient's joint as illustrated in a second one of the plurality of two-dimensional images of the patient's joint; and
- indicating a position of a second portion of a trapezoidal mating shape of the femoral portion of the cutting jig such that the second portion of a trapezoidal mating shape tangentially contacts an inner surface of a second condyle of the patient's joint as illustrated in the second one of the plurality of two-dimensional images of the patient's joint.
6. The method of claim 5 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- indicating a position of a second circular mating shape of the femoral portion of the cutting jig such that the second circular mating shape of the femoral portion contacts at least the first condyle of the patient's joint as illustrated in a third one of the plurality of two-dimensional images of the patient's joint, the contact of the second circular mating shape of the femoral portion posterior of the position of the first circular mating shape of the femoral portion; and
- indicating a position of a third circular mating shape of the femoral portion of the cutting jig such that the third circular mating shape of the femoral portion contacts at least the second condyle of the patient's joint as illustrated in the third one of the plurality of two-dimensional images of the patient's joint, the contact of the third circular mating shape of the femoral portion also posterior of the position of the first circular mating shape of the femoral portion.
7. The method of claim 6 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises indicating a position of a fourth circular mating shape of the femoral portion of the cutting jig such that the fourth circular mating shape of the femoral portion contacts at least one femoral condyle within a middle portion of the trochlear groove of the patient's joint as illustrated in a fourth one of the plurality of two-dimensional images of the patient's joint, the middle portion of the trochlear groove located between the contact of the first circular mating shape of the femoral portion and the second circular mating shape of the femoral portion along the trochlear groove of the patient's joint as illustrated in a fourth one of the plurality of two-dimensional images of the patient's joint.
8. The method of claim 7 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises indicating a position of a first circular mating shape of a tibial portion of the cutting jig and a second circular mating shape of the tibial portion of the cutting jig such that the first circular mating shape of the tibial portion and the second circular mating shape of the tibial portion contact the tibial anterior surface of the patient's joint as illustrated in a fifth one of the plurality of two-dimensional images of the patient's joint.
9. The method of claim 8 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- indicating a position of a third circular mating shape of the tibial portion of the cutting jig such that the third circular mating shape of the tibial portion contacts a medial tibial plateau surface of the patient's joint as illustrated in a sixth one of the plurality of two-dimensional images of the patient's joint; and
- indicating a position of a fourth circular mating shape of the tibial portion of the cutting jig such that the fourth circular mating shape of the tibial portion contacts a lateral tibial plateau surface of the patient's joint as illustrated in a seventh one of the plurality of two-dimensional images of the patient's joint.
10. The method of claim 9 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- indicating a position of a fifth circular mating shape of the tibial portion of the cutting jig such that the fifth circular mating shape of the tibial portion contacts a medial tibial plateau surface of the patient's joint as illustrated in an eighth one of the plurality of two-dimensional images of the patient's joint, the contact of the fifth circular mating shape of the tibial portion being posterior of the position of the third circular mating shape of the tibial portion; and
- indicating a position of a sixth circular mating shape of the tibial portion of the cutting jig such that the sixth circular mating shape of the tibial portion contacts a lateral tibial plateau surface of the patient's joint as illustrated in a ninth one of the plurality of two-dimensional images of the patient's joint, the contact of the sixth circular mating shape of the tibial portion being posterior of the position of the fourth circular mating shape of the tibial portion.
11. The method of claim 10 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises indicating a position of a seventh circular mating shape of the tibial portion of the cutting jig such that the seventh circular mating shape of the tibial portion contacts the lateral tibial plateau surface of the patient's joint as illustrated in a tenth one of the plurality of two-dimensional images of the patient's joint, the contact of the seventh circular mating shape of the tibial portion being between the contact of the fourth circular mating shape of the tibial portion and the sixth circular mating shape of the tibial portion on the lateral tibial plateau surface of the patient's joint as illustrated in the tenth one of the plurality of two-dimensional images of the patient's joint.
12. A system for creating a cutting jig for an arthroplasty procedure from a plurality of two-dimensional images, the system comprising:
- a network connection for receiving a plurality of two-dimensional images of a patient's joint the subject of the arthroplasty procedure, the plurality of two-dimensional images generated utilizing a magnetic-resonance imaging machine; and
- a computing device comprising; at least one processing device; and a non-transitory memory device in communication with the at least one processing device for storing one or more instructions that, when executed by the at least one processing device, cause the computing device to perform the operations of: reformatting at least a portion of the two-dimensional images to approximate a true anatomical coordinate of the patient's joint; locating a plurality of mating shapes within the reformatted plurality of two-dimensional images of the patient's joint, the plurality of mating shapes corresponding to a plurality of mating shapes of a cutting jig for use during the arthroplasty procedure; generating a milling program based at least on the placement of the mating shapes within the reformatted plurality of two-dimensional images of the patient's joint; and transmitting the generated milling program over the network connection to a milling device for milling the cutting jig based at least on the generated milling program.
13. The system of claim 11 wherein reformatting the two-dimensional images comprises:
- receiving an identification of one or more landmarks on the plurality of two-dimensional images of a patient's joint; and
- reorienting the plurality of two-dimensional images of a patient's joint based at least on the one or more landmarks.
14. The system of claim 11 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images comprises receiving an indication of a position of a first circular mating shape of a femoral portion of the cutting jig such that the first circular mating shape of the femoral portion contacts at least one femoral condyle within an anterior trochlear groove of the patient's joint as illustrated in a first one of the plurality of two-dimensional images of the patient's joint.
15. The system of claim 14 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- receiving an indication of a position of a first portion of a trapezoidal mating shape of the femoral portion of the cutting jig such that the first portion of a trapezoidal mating shape tangentially contacts an inner surface of a first condyle of the patient's joint as illustrated in a second one of the plurality of two-dimensional images of the patient's joint; and
- receiving an indication of a position of a second portion of a trapezoidal mating shape of the femoral portion of the cutting jig such that the second portion of a trapezoidal mating shape tangentially contacts an inner surface of a second condyle of the patient's joint as illustrated in the second one of the plurality of two-dimensional images of the patient's joint.
16. The system of claim 15 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- receiving an indication of a position of a second circular mating shape of the femoral portion of the cutting jig such that the second circular mating shape of the femoral portion contacts at least the first condyle of the patient's joint as illustrated in a third one of the plurality of two-dimensional images of the patient's joint, the contact of the second circular mating shape of the femoral portion posterior of the position of the first circular mating shape of the femoral portion; and
- receiving an indication of a position of a third circular mating shape of the femoral portion of the cutting jig such that the third circular mating shape of the femoral portion contacts at least the second condyle of the patient's joint as illustrated in the third one of the plurality of two-dimensional images of the patient's joint, the contact of the third circular mating shape of the femoral portion also posterior of the position of the first circular mating shape of the femoral portion.
17. The system of claim 16 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises receiving an indication of a position of a fourth circular mating shape of the femoral portion of the cutting jig such that the fourth circular mating shape of the femoral portion contacts at least one femoral condyle within a middle portion of the trochlear groove of the patient's joint as illustrated in a fourth one of the plurality of two-dimensional images of the patient's joint, the middle portion of the trochlear groove located between the contact of the first circular mating shape of the femoral portion and the second circular mating shape of the femoral portion along the trochlear groove of the patient's joint as illustrated in a fourth one of the plurality of two-dimensional images of the patient's joint.
18. The system of claim 17 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises receiving an indication of a position of a first circular mating shape of a tibial portion of the cutting jig and a second circular mating shape of the tibial portion of the cutting jig such that the first circular mating shape of the tibial portion and the second circular mating shape of the tibial portion contact the tibial anterior surface of the patient's joint as illustrated in a fifth one of the plurality of two-dimensional images of the patient's joint.
19. The system of claim 18 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- receiving an indication of a position of a third circular mating shape of the tibial portion of the cutting jig such that the third circular mating shape of the tibial portion contacts a medial tibial plateau surface of the patient's joint as illustrated in a sixth one of the plurality of two-dimensional images of the patient's joint; and
- receiving an indication of a position of a fourth circular mating shape of the tibial portion of the cutting jig such that the fourth circular mating shape of the tibial portion contacts a lateral tibial plateau surface of the patient's joint as illustrated in a seventh one of the plurality of two-dimensional images of the patient's joint.
20. The system of claim 19 wherein locating the plurality of mating shapes within the reformatted plurality of two-dimensional images further comprises:
- receiving an indication of a position of a fifth circular mating shape of the tibial portion of the cutting jig such that the fifth circular mating shape of the tibial portion contacts a medial tibial plateau surface of the patient's joint as illustrated in an eighth one of the plurality of two-dimensional images of the patient's joint, the contact of the fifth circular mating shape of the tibial portion being posterior of the position of the third circular mating shape of the tibial portion; and
- receiving an indication of a position of a sixth circular mating shape of the tibial portion of the cutting jig such that the sixth circular mating shape of the tibial portion contacts a lateral tibial plateau surface of the patient's joint as illustrated in a ninth one of the plurality of two-dimensional images of the patient's joint, the contact of the sixth circular mating shape of the tibial portion being posterior of the position of the fourth circular mating shape of the tibial portion.
Type: Application
Filed: Aug 6, 2015
Publication Date: Feb 11, 2016
Patent Grant number: 10139807
Applicant: Somersault Orthopedics Inc. (Pleasanton, CA)
Inventor: Ilwhan Park (Walnut Creek, CA)
Application Number: 14/820,473